Hi Marc, and welcome to the forum!
Marc Keller wrote:Is it possble to define the names of these HTML files in a help project?
No, absolutely not. Those names are critical, cannot be changed and you should not try to change them. Doing so would break all kinds of things.
Marc Keller wrote:The background is that we need to automatically export three different web helps into one and the same directory.
You can't do this like this and please don't try. WebHelp is an integrated whole with many internal references. Among other things, trying to put three separate
WebHelp collections into a single folder would make a mess of the search and keyword index functionality.
What you can do is combine your three projects, without changing them, and publish them as a single WebHelp with a single table of contents and search that operates on the whole thing. You do this by creating a master project and inserting the three other projects into it as modules. Or you can use one of the three projects themselves as the master and insert the other two into it as modules. This doesn't change the individual projects, because all you insert is a reference to the other projects. How to do this is explained here:
https://www.helpandmanual.com/help/hm_a ... dular.html
The only thing you need to be very careful of before publishing multiple projects together like this are duplicate topic IDs, which will cause errors. For example, if you have multiple projects with a topic that has the ID BriefIntroduction
then the HTML topic file briefintroduction.htm
will be exported to the same output folder multiple times, overwriting the previous version several times, and only the last version will actually get into your WebHelp.